nickjohnson wrote:In my case, the Loki has an onboard 3.3v regulator, and the latest revision of it connects the debug header's VTARG to the 5v rail - so the debugger needs to supply 5v, rather than 3.3. I did this because I think it should be more reliable: it doesn't result in reverse-biasing the 3.3v regulator, and it means any attached expansion boards that use 5v will see a correct voltage.
Pretty unique aproach. I'm wondering if it means it can no longer be properly programmed and debuged using a miniprog3, since PSOCprogrammer will sense no voltage and apply your chosen 5v or 3.3v to vtarg and SWD pins but your PSOC will have 5v (or 3.3v) minus regulator's dropout voltage.
nickjohnson wrote:If you're looking at doing a level shifter, selectable voltages for vtarg would probably be useful too.
I was going to require the board provides its own voltage and present it on Vtarg pin and use it on the second side of a dual voltage logic level translator. that way it's way more simple to handle.
nickjohnson wrote:How did you blow up your miniprog3?
84v AC rectified was accidentally connected to VCC rail while I was doing some experimentation on a litle board, fortunatelly it was not connected to a USB port at the time.